Materials That Block UV Rays: The Best Fabrics for Sun Protection

Learn about which fabrics and materials provide the most UV protection, as well as what factors to consider when choosing sun protective clothing.


Materials that block the sun’s ultraviolet radiation are used in many products such as sunglasses, shirts, and hats for sun protection.

Many fabrics can block some of the sun’s harmful rays because they are naturally resistant to fading from sunlight exposure, but some materials are better equipped for sun saftey than others.

We’ll dive into the best fabrics for sun protection, as well as what factors to consider when selecting the materials for UV-blocking capabilities.

Best Fabrics for Blocking UV Rays

Some of the best fabrics for blocking UV sun rays include:



Unbleached cotton contains natural lignins that act as UV absorbers (source). Bleached cotton, on the other hand, is a less than ideal choice for sun protective clothing, as dyes and chemicals break down the fabric’s composition.

Considering that bleached cotton is much more common in clothing than unbleached cotton, most cotton t-shirts are not ideal for sun protection.



Denim’s tight weave makes it a good protectant against the sun, but the material can feel heavy and stuffy in the heat of the day.

Polyester/Nylon & Synthetic Blends


The tightly woven fibers in nylon and polyester make it difficult for UV rays to penetrate the fabric. Synthetic blends like these are some of the most popular materials for UV clothing, as they offer a tight weave while remaining relatively lightweight and comfortable.



Similar to denim, canvas has a tight, thick weave that allows for great sun protection, but it can feel uncomfortably heavy as clothing, especially in the heat. Canvas works great for sun umbrellas or other awnings and shade tents designed to protect from the sun.



Linen is a tightly woven fabric made from the fibers of the flax plant. It is a popular natural fabric because it is durable and has the ability to block both UVA and UVB.

Linen also has the ability to control body temperature when worn in warmer climates. However, it wrinkles easily and some linen fabrics have looser weaves than others.



Wool is a popular natural fabric that can block both UVA and UVB rays. However, wool tends to hold onto odors and moisture, plus it can be itchy against the skin, making it an unpopular choice for sun protective clothing in the summer.

Fabrics to Avoid for Sun Protection

Not all fabrics are ideal for protecting against UV rays, and some are quite unsuitable.

Fabrics to avoid include:

  • Crepe
  • Bleached cotton
  • Viscose
  • Knits
  • Worn fabric

Factors That Affect A Fabric’s Sun Protection Ability

Stretch / Fit

Clothing that stretches can have less UV protection than clothing that does not stretch, as when the weave of the material loosens when the fabric stretches.

In fact, one study showed that a 15% stretch in cotton/lycra fabric cut a fabric’s UPF clothing in half! (source)

For this reason, looser-fitting clothes tend to provide better sun protection than tight-fitting items.


Some fabrics are pre-treated with UV-inhibitor chemicals to increase sun protection. However, these treatments can wash out over time, so don’t rely too much on the chemical treatments and give plenty of thought to the type of fabric itself being used in the clothing.

If you are purchasing clothing that has been pre-treated with special chemicals to block UV rays, read and follow all instructions for washing very carefully.

You may want to consider purchasing your own sun protection treatment for clothing that you can apply and re-apply yourself, at home. SunGuard Detergent is one popular UV-blocking additive that can be added to your laundry during a wash cycle.

Once added, it gives clothing an SPF factor of 30 and lasts up to 20 washes!

Weave Density

Clothing requires a tight weave to keep out the sun, as a looser weave allows for gaps and holes that allow UV rays to pass through.

weave holes

To test a fabric’s weave and measure the effectiveness of its sun protection, hold it up to a light (the sun works great).

If you can see any light through this cloth, the fabric may not offer sufficient sun protection.


Lighter-weight materials tend to offer less sun protection than materials with thicker, heavier-weight fibers (source), with the downside of course being that heavier materials are less comfortable in the summer.

Color / Dye

dyed fabric

Colored fabrics have higher UV protection – this is because they maintain their color due to the benzene atoms in the molecules that make up these dyes. This means that they can also absorb ultraviolet rays!

One study even found that dying fabric blue increased the UPF by 544%. Dying the fabric yellow gave a 212% increase (source).


The dryer the fabric, the better sun protection it will provide. Wet fabric can be up to 50% less effective than dry fabric.


Longer-sleeved shirts and pants will naturally provide better coverage and more sun protection as opposed to tank tops or short-sleeved shirts.

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